This enormous mushroom is often found growing in large fairy rings or arcs in woodland clearings. It is apparently widely distributed, but most common in the Pacific Northwest and Rocky Mountains. The caps are whitish at first, but by maturity have darkened somewhat, becoming dirty buff or tan. The mushrooms can get very large (caps up to 45 cm!), but they are ironically quite fragile when mature, and are hard to pick without breaking.

Whether the proper name for this mushroom is Clitocybe gigantea or Leucopaxillus giganteus (or something else) depends on how you define Clitocybe and Leucopaxillus. To my knowledge no DNA study has examined this taxon.

Description:

Ecology: Saprobic; growing alone, scattered, or in large arcs and fairy rings in open woods and woodland clearings with trees present; sometimes in disturbed ground; summer and fall; common in the Pacific Northwest and Rocky Mountains, but widely distributed in North America.

Cap: 8-45 cm; at first convex, then flat, eventually developing a central depression and becoming somewhat vase-shaped; dry; smooth; the margin inrolled at first, later wavy and sometimes obscurely lined; fragile in age; whitish at first, but buff to tan by maturity.

Gills: Running down the stem; crowded; whitish or buff, becoming nearly tan in age; some forking.

Stem: 4-10 cm long; up to 6 cm thick; more or less equal; dry; whitish, with tiny fibers that darken in age; base with copious white mycelium.

Clitocybe candida (AKA Leucopaxillus candidus) can approach the dimensions of Clitocybe gigantea; it has a cap that remains white through maturity, and is found growing gregariously under hardwoods in northern North America.